It is known to cool stacks of disc-type high power semiconductor device packages with interjacent water-cooled heat sink members. A variety of types of liquid cooled heat sink members, assemblies and methods have been proposed and patented for obtaining more effective cooling. However, because of a variety of practical problems the most conventional technique now commercially used still involves a relatively thick hollow heat sink member. The semiconductor devices are stacked between such members and clamped together. Each hollow heat sink member is individually connected to a manifold of rigid tubing. The hollow heat sink members have complex or convoluted passages in them which require complex casting techniques that increase the cost, as well as the thickness of the heat sink member. The coolant flow passages in the heat sink member are made as narrow as possible to make the member as thin as possible. Because of this, coolant must be circulated through the heat sink at a high rate of flow. This requires that the manifold supplying the liquid coolant to the heat sink members be able to withstand a high pressure without leaking. Rigid metal tubing with threaded couplings to each heat sink member can withstand such pressures without leakage. To simplify matters, the number of such connections is generally reduced by serially interconnecting small groups of heat sinks and paralleling the small groups. This, of course, means that the last member in each group is being cooled with coolant that has already been warmed by devices preceding it in its group. Accordingly, while this arrangement has its advantages, it also has disadvantages. For example, a group of devices may only be operated at the maximum performance level for the least effectively cooled device in each group.
With the heat sinks rigidly interconnected, replacement of semiconductor devices in the stack is not a simple matter. A further complication resides in the fact that semiconductor devices are registered on the heat sinks by means of a pin and complementary recess. The heat sinks must be spread far enough apart to allow the pins to become disengaged from the recess. In many instances several couplings in the coolant flow line must be disconnected. This is not only time consuming but each time a coupling is reconnected the risk of leakage is increased.
We have found an apparatus and method for more effectively cooling disc-type high power semiconductor device packages. It is more effective because liquid coolant is circulated directly in contact with the end faces of the packages, and the packages are maintained immersed in liquid coolant to provide cooling by conduction from the radial surfaces of the package. Thin heat sink members can be used because they need not be hollow. A unique elastomeric manifold integral with the assembly facilitates replacement of semiconductor device packages. Device package replacement is further enhanced by an improved device locating technique.